superenv: apply apr-1-config fix to 10.8+

Fixes Homebrew/homebrew#20417.
Closes Homebrew/homebrew#20474.

Signed-off-by: Jack Nagel <jacknagel@gmail.com>

Library/Homebrew/superenv.rb

@@ -217,8 +217,8 @@ class << ENV
     end
     # Fix issue with sed barfing on unicode characters on Mountain Lion
     s << 's' if MacOS.version >= :mountain_lion
-    # Fix issue with 10.8 apr-1-config having broken paths
-    s << 'a' if MacOS.version == :mountain_lion
+    # Fix issue with >= 10.8 apr-1-config having broken paths
+    s << 'a' if MacOS.version >= :mountain_lion
     s
   end